Fix a JavaScript regression encapsulating the problematic part into an if.
Other minor changes:
- dedicate a variable for the confirmation messages to improve i18n in the future (but also to avoid 80 characters and make lint happy)
- replace confirm with window.confirm (to make lint happy)
✅ The only usage of setTagText() seems to be in PhabricatorEditEngineSubtype and the input domain is just a string coming from phutil_utf8_strtoupper() (like "BUG") or null (default). The phutil_nonempty_string() will report alien values and this is OK.
Also, the method was returning a bool, and it still returns a bool.